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| Asteroid Florence will be a big miss, as opposed to Florence and the Machine, which is a big hit. |
Florence is the largest near-Earth asteroids on record at Nasa, measuring some 4,4 kilometres in size, about half the size of the meteorite that ended the age of the dinosaurs, which likely measured some 10 km across.
This is the same estimated size as the meteorite that made the world’s largest meteorite crater, the 300-km hole between Johannebsurg and Welkom, with its center at Vredefort in the Free State.
Size is the only difference between asteroids and meteorites. Any large rocky body orbiting the Sun is
referred to as an asteroid or minor planet, while smaller particles are meteoroids. When astronomers stop debating how to define dwarf planets, they may also decide to just refer to all asteroids as meteoroids.
For astronomers do agree that a small asteroid, or large meteoroid, that survives the fiery trip through Earth’s atmosphere is called a meteorite.
Fist-sized meteorites have shot through roofs, but it is the shock wave of bigger meteorites that causes the most damage. The Chelyabinsk asteroid, estimated to be about 20 metres wide when entered Earth’s atmosphere over Russia in February 2013, generated a shock wave that broke windows in over 3 600 apartment blocks, injured over 1 600 people, some of them also suffering radiation burns as the asteroid flashed over head 30 times brighter than the sun.
While hard to see against the backdrop of stars, the slow moving Asteroid Florence will be visible in small telescopes until Sunday. Scientists will use its passing to practise their radar observations and the resulting radar images should show the exact size of Florence and surface detail down to 10 meters.
